Manufacture of glycols



July 22, 1941. F. J; sMl'rH MANUFACTURE 0F GLYCOLS Filed Junevl 25. 1939 Patented July 2v2, 19.41

UNITED STATES PATENT OFFICE MANUFAUTURE or GLYcoLs Frank, J. smith, Baltimore. Md., minor to Standard Oil Company, Chicago, Iii., a corporation of Indiana l Application June 25 193s, semi No. 215,744

' (ci. 26o-635) 7 Claims'.

valuable glycolslirom low-priced fuel gases and,

particularly cracking still gases by treatment with `barium peroxide in such manner that substantially no chemicals are destroyed in the process but are continually recycled for repeated use. Further objects of the invention will be apparent from the following description. The process is illustrated by a drawing which shows dlagrammatically one form of apparatus and material routing for carrying out the process.

Referring to the drawing, hydrocarbon'gases which may be derived from the cracking oi petroleum oils, from the conversion of carbon monoxide and hydrogen into motor fuels by the Fischer process. or from some other source of unsaturated gases, are introduced by line i into reaction chamber Ii. The pressure em- CII ployed in the reaction may suitably be atmospheric pressure or slightly higher pressure. e. g., 5 to 50 pounds per square inch, depending on the pressure of the gases available.

The gases are conducted upward through the tower Il where they are contacted, by means of suitable baiiies, with a downowing solution oi reagents hereinafter described. The solution maybe introduced by line i2 and, if desired, it may be withdrawn from the base of the tower Ii by line I3 and recycled by pump i4 and line I5 back to the tower to increase the concentration of reaction products. The olens contained in the gas are substantially converted into glycols and the residual .gas escapes by line I8 to the fuel gas vmain i1.

The solution employed in reaction chamber H is comprised of barium peroxide partially dissolved and suspended in water. In order to bring about the reaction between barium peroxide and the olens I introduce CO2, by line i8, into the gas stream entering the tower.. The CO2 converts the barium peroxide into barium carbonate in the presence oi' the olens, thereby producilliigvin the case of ethylene the following reac- The barium carbonate which is formed remains suspended in the reagent solution and is recycled until the concentration of the desired glycol reaches an economical strength, for example 5 to 10%, or more. In fact, the glycol concentration may conveniently be built up to about 20% within reaction chamber ii.

When the glycol concentration has reached the desired value a portion of the solution is with- -drawn from the system by line i9 leading to lter 20 where the suspended barium carbonate is removed by line 2|. The filtered solution is then conducted by line 22 through heat exchanger 23 into evaporator 24 where substantially all of the water in the solution is removed by vapor line 25. If desired, evaporator 24 may Vibe a multiple effect evaporator, operating under partial vacuum. The crude glycols obtained in evaporator 24 are withdrawn by line 26 to stora'ge 21. The vapors are conducted by line 25 through exchanger 23 where the water is substantially condensed and led by line 28 to mixer 29 hereinafter described.

Barium carbonate in filter 20 is conducted by line 2| to converter 30 which is an insulated chamber suitably equipped with trays and agitators for drying the barium carbonate and subjecting itfto high temperature whereby it is converted into barium oxide according to the following reaction:

BaCOa-l-heat-)BaO-i-COz This reaction is brought about by introducing superheated steam byline 3i and maintaining a temperature within converter 30 oi about 800- l200 F. 'I'he steam and CO2 are conducted by line 32 to heat exchanger 33 Vand thence by line 34 to condenser 35 where steam is condensed and separated in trap 36, the CO2 being conducted by line 31 back to the hydrocarbon stream entering reaction chamber Il. Heat abstracted from the spent steam in exchanger 33 is employed to evaporaor uby circulating'liquid from the evapora or pump 38 throu lines 39 and 40. gh! exchanger 33 by The barium oxide is withdr Wn from the base of converter 30 and conducty by conveyor 4I to calciner 42 wherein the'barium oxide is agitated and heated at a temperature of about 850 to 1000 F. in the presence of excess air and preferably out of contact with combustion gases introduced by burner 43. 'Ihe barium oxide is `converted by this treatment into barium peroxide' which is withdrawn into mixer 29 where it is first cooled and then. mixed with water introduced by line 28. barium peroxide and water is forced by pump Il through line I2 leading to the upper part of reaction chamber II o r, if desired, it may be introduced by line 45 along with any CO2 which it may contain into the lower section of reaction chamber Il.

'I'he olefin gases which I may employ in my process may suitably contain about 20 to 50% of oleflns and a gas containing about 80% of oleflns is satisfactory. The gases may be withdrawn directly from the cracking' still in which case -they will contain methane, ethane and some hydrogen. If desired the cracking still gases may be separated into their components, for example the C2. Ca and C4 fractions by al suitable conf densing and fractionating system and the Cz, Ca or C4 fractions may be separately treated according to my process, thereby lproducing ethylene, propylene or butylene glycols as desired with relatively little contamination from other glycols or I may employ the gas mixture without separation and subsequently separate the glycols by suitable fractionation.

Although I have described my process with respect -to a specific embodiment thereof, I do not intend that it be limited except as described The resulting slurry of 2. The process of claim 1 wherein the barium carbonate is converted into barium oxide by heating in the presence of superheated steam and carbon dioxide recovered therefrom is recycled to said contacting step.

3.- The process according to claim 1 wherein the glycol solution, after removing barium car- Y bonate, is evaporated and the water separated therefrom is recycled to said contacting step.

4. The process according to claim l. wherein the glycol 'solutionl after removing barium carbonate, is evaporated and the water is mixed with said recovered barium peroxide before recycling to said contacting step.

5. The process of making ethylene glycol from a mixture of cracking still gases which comprises condensing the Cz, Ca and Cr fraction of said gases, separating the Cz fraction by fractional distillation, adding carbon dioxide to said Cz fraction containing ethylene and introducing the resulting gas mixture into a reaction zone, contacting said gas mixture in said reaction 'zone with barium peroxide whereby said ethylene is converted into ethylene glycol and barium car. bonate is formed, removing barium carbonate from the reaction products. converting the barium carbonate into barium peroxide and recycling said barium peroxide to said reaction zone.

6. The process of making glycols directly from I olefin hydrocarbon gases which comprises mixing carbon dioxide with said olefin gases, contacting `the resulting gas mixture with barium peroxide in the presence of water, whereby said barium peroxide is activated by said carbon dioxide in intimate association with said olefin gases, bari'- um carbonate is formed and said olefin gases are converted into the corresponding glycols, separating barium carbonate from said reaction mixture and recovering said glycols from the remaining solution. l

'1. The process of claim 6 wherein the oleiin employed is ethylene.

l FRANK J. SMITH. 

